1. Field of the Invention
The present invention relates to electrical connectors, more particularly to electrical connectors with additional signal transmission means.
2. Description of Related Art
In information technology, Universal Serial Bus (USB) is a serial bus standard to interface devices. USB can connect computer peripherals such as computer mouse, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of those devices, USB has become the standard connection method.
The design of USB is standardized by the USB Implementers Forum (USB-IF), an industry standards body incorporating leading companies from the computer and electronics industries. As of 2006, the USB specification was at version 2.0 (with revisions). The USB 2.0 specification was released in April 2000 and was standardized by the USB-IF at the end of 2001. The USB 2.0 specification is available from website: http://www.usb.org/home. Previous notable releases of the specification were 0.9, 1.0, and 1.1. Equipment conforming to any version of the standard will also work with devices designed to any previous specification (known as: backward compatibility).
The USB 2.0 specification defines several types of USB connectors such as Standard-A and Standard-B plugs and receptacles. Type-A plugs only mate with type-A receptacles, and type-B plugs only mate with type-B receptacles. FIG. 19 shows an existing USB 2.0 Standard-A plug 8, the Standard-A plug 8 includes an insulative plug tongue portion 80 formed of an insulating material, four conductive contacts 81 fixed on the insulative plug tongue portion 80. The four conductive contacts 81 are located orderly from left to right to transfer power, D−, D+ and ground signals, respectively, the two central conductive contacts constitute a pair of differential contacts used to transfer/receive data. However, the current USB 2.0 version has a top data-transfer rate of 480 megabits per second which does not efficiently meet requirement of data transmission speed for optical drives such as DVD, Blue-ray and HD DVD. Recently, some approaches have been made to add more electrical contacts as shown in the conending application Ser. No. 11/818,100, and others apply further optics to the connector.